In general, transparent, electroconductive substrates are obtained by filming an oxide such as indium-tin oxide (hereinafter referred to as "ITO") or antimony-tin oxide ("ATO") on a glass support by sputtering or CVD, or are obtained by coating a transparent, electroconductive ink containing a powder of ultra-fine, electroconductive particles having a particle size smaller than the smallest wavelength of visible rays on a support such as a glass support, followed by drying it on the support, which is then baked at high temperatures of 400.degree. C. or higher.
However, the former method mentioned above needs expensive devices and its producibility and yield are low, by which, therefore, it was difficult to obtain low-priced, transparent, electroconductive substrates. On the other hand, the electroconductive film formed on the support by the latter method mentioned above has some gaps remained between the ultra-fine particles thereon so that light scatters on the film, which, therefore, have poor optical properties. In order to fill the gaps, heretofore, a process has been proposed in which a glass-forming component is incorporated into the transparent, electroconductive ink prior to forming the transparent, electroconductive substrate. However, the glass-forming component is problematic in that it exists between the ultra-fine, electroconductive particles, thereby increasing the surface resistivity of the electroconductive film to be formed on the support. For this reason, therefore, it was difficult to satisfy both the optical characteristics of the transparent, electroconductive substrate and the desired conditions for the value of the surface resistivity of the same by the above-mentioned latter method. In addition, the transparent, electroconductive substrate formed by the above-mentioned latter method has been found to have another problem about its weather resistance in that, when it is allowed to stand in air for several months, the resistance of the film coated thereon increases probably because of the deterioration of the film itself in the presence of water in air.
The present invention has been made in consideration of these problems in the related prior arts, and its object is to provide a transparent, electroconductive substrate having a small surface resistivity and-having excellent optical characteristics and weather resistance and to provide a method for forming the substrate.